摘要
活塞是內(nèi)燃機(jī)的關(guān)鍵零件之一，其質(zhì)量直接決定著內(nèi)燃機(jī)的工作性能。中凸變橢圓活塞屬于非圓截面零件，其型面特殊，加工相對困難，成為活塞研究領(lǐng)域的一個(gè)重要課題。
根據(jù)我國活塞加工的現(xiàn)狀，本文改變傳統(tǒng)車床結(jié)構(gòu)，設(shè)計(jì)一種新的活塞車床布局結(jié)構(gòu)，床身為倒“T”字型結(jié)構(gòu)，根據(jù)中凸變橢圓活塞的加工要求，設(shè)計(jì)了數(shù)控機(jī)床的整體結(jié)構(gòu)，運(yùn)用Pro/E軟件建立了三維模型。同時(shí)用HyperWorks對平臺與刀架進(jìn)行了有限元分析。使直線電機(jī)驅(qū)動的刀座結(jié)構(gòu)設(shè)計(jì)輕量化，以降低在高速往復(fù)運(yùn)動過程中產(chǎn)生的慣量，減少跟隨誤差。
設(shè)計(jì)了基于TURBO PMAC+PC的雙CPU開放式數(shù)控系統(tǒng)結(jié)構(gòu)。X軸進(jìn)給機(jī)構(gòu)采用伺服電機(jī)加直線電機(jī)雙層驅(qū)動結(jié)構(gòu)，通過光柵反饋形成全閉環(huán)控制；Z軸進(jìn)給運(yùn)動采用伺服電機(jī)加滾珠絲杠驅(qū)動；主軸采用伺服電機(jī)驅(qū)動，通過TUBRO PMAC實(shí)時(shí)控制主軸轉(zhuǎn)過的角度和X軸徑向位移成聯(lián)動關(guān)系，實(shí)現(xiàn)活塞橢圓截面的加工，控制X軸和Z軸的聯(lián)動實(shí)現(xiàn)活塞中凸形面加工。這種加工方法與傳統(tǒng)的靠模仿形加工相比具有柔性好、加工精度高等特點(diǎn)。
開發(fā)了基于WINDOWS平臺的開放式數(shù)控系統(tǒng)。應(yīng)用TURBO PMAC運(yùn)動控制卡提供的動態(tài)鏈接庫(PCOMM32)在WINDOWS利用VC++6.0平臺上開發(fā)了上位機(jī)軟件，完成了開放式非圓活塞數(shù)控系統(tǒng)管理軟件模塊的設(shè)計(jì)。PMAC完成實(shí)時(shí)控制部分任務(wù)，軟件開發(fā)主要完成上位機(jī)非實(shí)時(shí)控制部分任務(wù)，實(shí)現(xiàn)了數(shù)控系統(tǒng)的基本功能。
根據(jù)中凸變橢圓活塞車削特點(diǎn)，選用基于TURBO PMAC卡的各運(yùn)動軸聯(lián)動的活塞車削方式，通過廠家提供的活塞數(shù)據(jù)，進(jìn)行活塞車削實(shí)驗(yàn)，最終的實(shí)驗(yàn)證明遠(yuǎn)遠(yuǎn)優(yōu)于傳統(tǒng)的旋轉(zhuǎn)電動機(jī)+滾珠絲杠，能夠滿足活塞加工的精度要求，試驗(yàn)結(jié)果表明系統(tǒng)達(dá)到了預(yù)期的設(shè)計(jì)要求。
以上研究只是針對中凸變橢圓活塞的加工而提出的，對于我國活塞加工具有一定的理論意義和重要應(yīng)用價(jià)值。對于其它非圓截面零件的加工也具有一定的指導(dǎo)意義。

關(guān)鍵詞：中凸變橢圓活塞；數(shù)控車床；直線電機(jī)；刀架；TURBO PMAC

Abstract
Piston is one of the key parts of internal combustion engines, which directly determines the work performance of internal combustion engines. Middle-convex and varying ellipse piston turning is a special noncircular cross section, and its special molding surface brings difficulty for its design and processing. This becomes an important task in the researching domain of the piston.
According to China's processing status of the piston，diffent from tradition，this paper presents a design of the piston CNC lathe adopting inversion T-shape structure and using Pro/E to establish machine’s solid model. Make analysis of mechanical properties on tool holder and work platform by HyperWorks. In order to make the designed knife block structure of liner motor lightweight. In order to reduce inertia producing in the process of motor’s high speed reciprocating motion and follow error.
Designed open CNC system structure based on TUBRO PMAC+PC. X-axis feed movement using servo motor and linear motor double-driven mechanism, realizing loop control through raster feedback; Z-axis feed motion with servo motor and ball screw drive; Adopting servo control, Spindle coordinates the turn of the spindle shaft angle and X-axis radial displacement by TUBRO PMAC controller; The linkage of X-axis and Z-axis can realize the piston convex surface processing. In contrast with the traditional hard profiling method, the method has the advantages of good flexibility, high processing efficiency and high degree of accuracy.
The Open CNC system and softwae has been developed based on WINDOWS platform. Non-circular Pistons open CNC system software designed by the dynamic link library (PCOMM32) PMAC motion control card provided in the WINDOWS platform. The real-time control tasks were completed by PMAC. Software developments by visual c++ on PC focused on major some tasks of non-real-time control and achieve the NC system's basic functions.
According to the middle-convex and varying ellipse piston turning’s processing characteristics, we choose the TURBO PMAC‘s movements control of the turning axis. We make the piston turning experiments by date which is provided from piston manufacturer.It is far superior to the traditional aspects of the rotary motor + ball screw will be able to meet the requirements of the Pistons processing. Testing results show that the system has achieved the expected results of the design requirements.
The conclusions studied is specially present for middle-convex and varying ellipse piston turning. Research has certain theoretical significance and an important value in the piston of China's processing. what's more, it also can be referenced for other noncircular cross section works.

Key Words: Middle-convex and varying ellipse piston, CNC lathe, Linear motor, Knife rest, Turbo PMAC

目 錄
摘要 I
目 錄 I
CONTENTS III
第一章 緒論 - 1 -
1.1本課題的來源及背景 - 1 -
1.2非圓截面零件常規(guī)的成型技術(shù) - 1 -
1.3中凸變橢圓活塞型面的傳統(tǒng)加工方法 - 2 -
1.4國內(nèi)外現(xiàn)狀 - 4 -
1.4.1活塞異型面車削數(shù)控車床的研究發(fā)展現(xiàn)狀 - 4 -
1.4.2活塞異型面車削數(shù)控系統(tǒng)的研究發(fā)展現(xiàn)狀 - 5 -
1.5本課題研究的目的和主要內(nèi)容 - 5 -
1.5.1本課題研究的目的 - 5 -
1.5.2本課題的主要內(nèi)容 - 6 -
第二章 中凸變橢圓活塞型線加工原理及機(jī)床總體設(shè)計(jì) - 7 -
2.1中凸變橢圓活塞型線車削加工原理 - 7 -
2.2中凸變橢圓..